Aptus Massboost, 5 L

Prevent Calcium and Magnesium Gaps at the Moments That Matter Most, 5 L

Calcium and magnesium are often treated as background nutrients, addressed only when visible deficiencies appear. In reality, demand for both spikes at specific points during flowering, and meeting that demand on time determines whether flowers and stems develop with structural density. Massboost is a calcium-magnesium bloom additive formulated around that timing, applied during weeks 3, 5, and 7 of flower, the points when Ca and Mg demand peaks.

Massboost ships in a 5 L container, sized for multi-room growers applying it at weeks 3, 5, and 7 of flower.

Key Features & Benefits

• Week-specific Ca-Mg delivery — targets weeks 3, 5, and 7 of flower, the periods of peak structural demand, rather than applying across the full cycle.
• Calcium for cell-wall strength — supports the structural integrity of flowers, stems, and new tissue during intensive growth.
• Magnesium at the core of chlorophyll — keeps photosynthesis running at full capacity as the plant redirects energy into flower production.
• Vegetative-phase use if needed — can be applied at 2.5-5 ml per 5 gallons during veg to address early Ca or Mg deficiencies before they compound.
• Pairs with Aptus Liquid Base — which contains no added calcium, making Massboost or Mineral-CalMag a required companion in the Aptus system.

Who Should Use Aptus Massboost

Growers feeding through the flowering phase who need to prevent Ca and Mg deficiencies at weeks 3, 5, and 7 without disrupting the rest of their feed program, and anyone running Aptus Liquid Base, which requires a dedicated Ca source, with the 5 L size matched to garden scale.

About Aptus Massboost

Aptus Plant Tech began developing soil- and plant-science-based nutrient research in the Netherlands in the 1990s and has grown into a hydroponic nutrient supplier distributing across Europe, North America, and Australia. Massboost applies Ca and Mg at 5-10 ml per 5 gallons during flowering weeks 3, 5, and 7, and at 2.5-5 ml per 5 gallons during veg if deficiency signs appear; because Aptus Liquid Base contains no added calcium, Massboost or Mineral-CalMag is required in any feeding program built around it.

Frequently Asked Questions

Why apply Massboost during specific weeks rather than continuously?

Plant demand for calcium and magnesium spikes at specific developmental stages in flower. Targeting weeks 3, 5, and 7 delivers Ca and Mg when they're needed most rather than diluting the application across the full cycle.

Can Massboost be used during the vegetative stage?

Yes, at 2.5-5 ml per 5 gallons if calcium or magnesium deficiency signs appear during veg. The full bloom-stage dosage of 5-10 ml per 5 gallons applies during weeks 3, 5, and 7 of flower instead.

How does Massboost pair with Aptus Liquid Base?

Liquid Base contains no added calcium, so Massboost (or Mineral-CalMag) is required to supply Ca and Mg when building a feeding program around Base. Skipping both would leave the program without a dedicated calcium source.

What separates Massboost from a standard Ca-Mg supplement?

Massboost is formulated for targeted, week-specific application during flowering rather than continuous background dosing, matching the actual demand pattern of the plant through the bloom cycle. That timing is the core difference from a flat-rate calcium-magnesium product.